Detailed Explanation:
Preliminary energy modeling focuses on the building's massing, orientation, thermal comfort ranges, and energy supply sources. Plug and process loads are typically omitted at this stage as they are highly variable and depend on specific occupant behavior and equipment usage. LEED focuses on the building's core energy performance during preliminary analysis.

Pilot Credit registration is required when documenting a LEED Pilot credit. This is to ensure that the project team has access to the latest pilot credit language and requirements, and that USGBC can track the usage and feedback of the pilot credits. The other options are not required for documenting a pilot credit, although they may be helpful or applicable for other credits.
Reference: LEED Pilot Credit Library, Getting Started, page 1.

SRI generally decreases with age
The Solar Reflectance Index (SRI) is a measure of the ability of a surface to reflect solar heat, as shown by a small temperature rise. It is calculated using the values of solar reflectance and thermal emittance of the surface. The higher the SRI, the lower the heat island effect. However, SRI generally decreases with age due to factors such as weathering, dirt accumulation, and biological growth. Therefore, the Sustainable Sites Credit, Heat Island Reduction takes into account both new and three-year aged SRI values for roofing material to ensure that the material maintains a high level of reflectance over time.

According to the LEED Reference Guide for Building Design and Construction1, the Indoor Environmental Quality Credit, Indoor Air Quality Assessment, Option 1. Flush-Out requires the project to perform a building flush-out by supplying a total air volume of 14,000 cubic feet of outdoor air per square foot of gross floor area while maintaining an internal temperature of at least 60°F and no higher than 80°F and relative humidity no higher than 60%. The gross floor area of the building is 1,000 ft2 and the ceiling height is 10 ft, so the required volume of supply air for the entire building flush-out is:
14,000 ft3/sf x 1,000 sf = 14,000,000 ft3

Explanation
According to the LEED v4: Building Design + Construction Guide, the owner or an owner's representative must be a member of the integrated project team for the Integrative Process Prerequisite, Integrative Project Planning and Design.The owner or an owner's representative is responsible for establishing the project's vision, goals, budget,and schedule, as well as defining the owner's project requirements (OPR) and participating in the design charrettes and reviews1.The owner or an owner's representative also plays a key role in ensuring the continuity and alignment of the project's performance and environmental objectives throughout all phases of the project1.
The other choices are not mandatory members of the integrated project team, although they may be involved in the integrative process depending on the project's scope and needs.The general contractor is typically hired after the design phase and may not be involved in the predesign and schematic design analyses required by the prerequisite1.A LEED AP is a professional who has demonstrated knowledge and experience in applying the LEED rating system, but is not required to be part of the integrated project team, although it is recommended and rewarded by the LEED credit, Integrative Process1.The project's mechanical engineer is one of the possible design consultants who may contribute to the integrative process, especially for the energy-related systems analysis, but is not required to be part of the integrated project team1.
References: LEED v4: Building Design + Construction Guide, Integrative Process Prerequisite, Integrative Project Planning and Design, Requirements1